#include<stdio.h>

int main(){

    float a,b;
    char c;
    scanf("%f %f %c",&a,&b,&c);
    switch(c){
        case '+':printf("%f",a+b);break;
        case '-':printf("%f",a-b);break;
        case '*':printf("%f",a*b);break;
        case '/': {
            if (b == 0){printf("除数不能为0");break;}
            else {printf("%f", a / b);break;}
        };
    }
   return 0;
}